Keys didn't have anything to do with it, he stole user funds. Users deposited cash and crypto assets with the exchange in order to trade. Gerald sold some of t

Keys didn't have anything to do with it, he stole user funds. Users deposited cash and crypto assets with the exchange in order to trade. Gerald sold some of the users' crypto to buy nice things for himself. This was theft. When the price of bitcoin went up, the dollar value of the crypto he owed to users went up, and he could no longer cover it. He may have only stolen $10 million or so, but he ended up owing $100s of millions.